CVE-2025-39726
The Linux kernel's s390/ism driver fails to enforce that only one request‑response sequence can occur per ISM function at a time, allowing concurrent commands to overwrite each other and potentially cause device errors, DMA issues, or lost/executed‑twice commands. This flaw is rated critical with a CVSS base score of 9.8. A patch has been released to serialize command processing and fix the concurrency issue.
An official fix is available, so this entry is kept for 30 days and then removed automatically.
Who is affected
Linux kernel versions that lack the s390/ism concurrency fix (e.g., the 6.16 series referenced in the CPE data).
Real-world impact
Attackers could trigger the race condition to corrupt ISM function state, leading to connection breakdowns, invalid DMA events (PEC 2/3A), and possible denial of service or unintended command execution.
Why this severity
CVSS 3.1 metrics show Attack Vector: Network, Attack Complexity: Low, Privileges Required: None, User Interaction: None, Scope: Unchanged, with High impacts to Confidentiality, Integrity, and Availability, yielding a base score of 9.8 (Critical).
What to do about it
- 01Obtain the latest Linux kernel update from your distribution that includes the s390/ism concurrency management fix.
- 02Install the kernel update according to your distribution's standard procedure.
- 03Reboot the system to load the patched kernel.
NVD-referenced vendor advisory (the NVD description states the vulnerability has been resolved in the Linux kernel).
Timeline
- Sep 5, 2025 · Sep 5, 2025PublishedDisclosed and added to the National Vulnerability Database.
- Jul 30, 2026 · 6d agoAdvisory updatedThe NVD record was last revised.
- Jul 30, 2026 · 6d agoOfficial fix availableA vendor patch or mitigation now exists — see the remediation steps above.